Surface high speed craft



May 25, 1937. Q Q HAMPDEN 2,081,868

SURFACE HIGH SPEED CRAFT Filed June 3, 1936 2 Sheets-Sheet 1 Fig.1. A

May 25, 1937. G. c. E. HAMPDEN SURFACE HIGH SPEED CRAFT Filed June 5, 1956 2 Sheets-Sheet 2 Fig. 6.

Fig. 5.

Patented May 25, 1937 UNi'iE STATES PATNT FEE.

2,081,868 SURFACE HIGH SPEED CRAFT Geoffrey Cromwell Edward Hampden, Ewelme, England, assignor to J. Samuel White & Company Limited, East Cowes, Isle of Wight, England, a British company Application June 3, 1936, Serial No. 83,365 In Great Britain June 13, 1935 6 Claims. (Cl. 114-66.5)

This invention relates to surface high speed rear edges respectively different inclinations to craft of the type in which the hull of the vessel the horizontal or different curvatures. is provided with downwardly directed struts With regard to the hydrofoils, the portions of which carry hydrofoils on which, when speed is each foil which lie and project from opposite attained, the hull is supported above or partly S es of t e tr t y Sweep backwards from above the surface of the water. The object of the e rut 0 t t he portions of each foil invention is to eiiect such improvements in the f rm an angle with ea h o her t he strut which structure and disposition of the hydrofoils and carries them. Each of these hydr f il portions the struts on which they are mounted as to demay be straight as to its leading edge or curved crease the resistance offered by these parts, to soas to present a convex edge in the forward 10 increase the lifting power of the hydrofoils and direction. Further, one or both portions of each to lessen the tendency of the struts and foils foil, which lie on opposite sides of the strut which to be fouled by floating matter such as seaweed. carries them, may be inclined with respect to a According to this invention each strut prohorizontal plane.

jecting downwardly from the hull of the vessel In the accompanying drawings- 15 carries a set of hydrofoils mounted so as to Figure 1 illustrates, in side elevation, one form project from the opposite sides of the strut, that of surface craft embodying the invention, is in a transverse direction with respect to the Figure 2 is a sectional plan on the line IIII hull. Thus each set of hydrofoils spaced apart of Figure 1, 0 in the vertical direction are carried and mounted Figure 3 is a section on the line III-III of as indicated on a single strut only, thus lessening Figure 2, the resistance when the vessel is in motion as Figure 4 is a view similar to that of Figure 2 compared with previously known constructions but showing a. modified arrangement of the struts in which a set of hydrofoils is carried by a pluand hydrofoils, rality f struts, Figure 5 illustrates, on an enlarged scale, the

Each strut may be of streamline cross-section arrangement of the hydrofoils on each of the and may be tapered in thickness, that is in the struts shown in Figure 4,

transverse directions, from its root or base where Figures 6, '7, 8 and 9 are similar views of it is attached to the hull down towards its lower four further hydrofoil arrangements which may end. This tapering is so determined that the be employed, 30 end portion of the strut which carries at least Figures 10, 11 and 12 show in side elevation the two lowermost hydrofoils in the set is the and on an enlarged scale three forms of strut, part of the strut which is thinnest in transverse and directions. With respect to the water-line of Figures 13 and 14 are views similar to that of the hull when resting on the water, the strut is Figure 3 showing respectively two further mod- 35 inclined or directed rearwardly, the strut being ified arrangements of the hydrofoils on the struts. either straight or curved as to its leading edge In the arrangement illustrated in Figures 1, with the convex side of this curve directed for- 2 and 3, the craft comprises a hull A furnished wardly. By thus rearwardly directing the strut, with three struts B B and 5 the struts B .10 the hydrofoils mounted thereon will not lie imand B being spaced apart transversely with remediately over each other but each foil is set spect to the length of the hull A and extending somewhat further back than the next higher foil downwards from the forward part thereof, whilst with respect to a vertical plane. The dimenthe third strut B extends downwardfrombeneath sions of each strut measured in the fore and the after portion of the hull on the centre line i aft direction, which may conveniently be desigthereof. Each of the struts B B B is furnated as the width of the strut, may vary from nished with a set of hydrofoils C arranged one the root or base towards the lower end. Thus above the other and projecting from opposite the root part may have an appreciably greater sides of the strut so as to extend transversely width than the lower part or parts of the strut to the length of the hull. As will be clearly seen and strength thereby added to the root part from from Figure 2, the set of hydrofoils C on each 50 the aspect of attaching it to the hull. The width strut B B or B is supported solely by that I may be tapered off throughout the length of the strut and each hydrofoil is formed to a known strut or the tapering may be only arranged over aerofoil shape and section. a part of its length. This tapering may, for Each of the struts is of streamline cross-secinstance, be effected by giving the forward and tion as shown in Figure 2 and is tapered in thick- 55 Cal ness from its root or base where it is attached to the hull A towards its lower end. Thus, as will be seen from Figure 3, this tapering is so determined that the end portion of the strut which carries at least the two lowermost hydrofoils C in the set is the part of the strut which is thinnest in transverse direction, that is to say, in directions transverse to the length of the hull. Similarly, as will be seen from Figure 1, the dimensions of each strut measured in the fore and aft direction decreases from the root or base where the strut is attached to the hull A to the lower end of the strut so that strength is added to the root part of the strut from the aspect of attaching it to the hull. The hydrofoils C on opposite sides of each strut are inclined upwards with respect to the horizontal as clearly shown in Figure 3, so that the parts of the hydrofoils on one side of the strut form a downwardly directed angle with those on the other side thereof.

When the vessel is moving forward through the water the action of the hydrofoils C lifts the vessel until, when speed is attained, the hull A is supported above the surface of the water by the hydrofoils C.

In the modified arrangement illustrated in Figure 4, a single strut B is arranged on the centre line of the hull A and extends downwards from beneath the forward portion thereof. Two further struts B and B are spaced apart transversely with respect to the said centre line of the hull and extend downwards from beneath the after portion of the hull. Each of these r struts is not only streamlined as described with reference to Figures 1, 2 with a set of hydrofoils C wards from the associated portions of each foil form and 3, but is furnished which are swept backstrut so that the two a forwardly directed drofoil being straight, as shown in Figures 4 and 5, each foil may be curved as shown for example at C in Figure 6, with the convex edge of the hydrofoil directed forwards, that is to say, towards the bow of the vessel.

In the modified arrangement illustrated in Figure 7, the strut D is furnished with a set of hydrofoils C which are not only swept backwards as described with reference to Figure 5, but are so disposed on the strut that a portion of the leading edge of the latter projects appreciably in advance of the leading edges of the hydrofoils. In Figure 8, the forward or leading edge of the strut D projects appreciably in ad Vance of the adjacent leading edges of the hydrofoils C whilst the trailing edge of the strut extends behind the trailing edges of the hydrofoils. In Figure 9 the leading edge of the strut D projects in advance of the leading edges of the hydrofoils C whilst the trailing edges of these hydrofoils lie somewhat behind the trailing edge of the strut. With any of the constructions illustrated in Figures '7, 8 and 9, a tendency for the strut and foils to be fouled by floating matter such as seaweed is materially decreased.

Instead of the struts being directed substantially vertically downwards from the hull as shown in Figure 1, each strut may be inclined or curved backwards, that is to say, towards the after portion of the vessel. Thus, for example, as illustrated in Figure 10, the strut E is straight as to its leading and trailing edges, but is inclined backwards, the strut being tapered from its root to its free end as above described. In

this arrangement the hydrofoils E are disposed in echelon so that any one hydrofoil lies somewhat farther aft than the next higher hydrofoil. As will be seen from this figure the angles of incidence of the higher foils are somewhat greater than those of the lower foils so that increased initial lifting power is obtained when the vessel is getting up speed and, further, any tendency to nose-dive will be counteracted by the higher angle of incidence of the upper hydrofoils in the set. This variation in the angle of incidence of the hydrofoils may be present in each set of hydrofoils or only in the forward set or sets or only in the set or sets disposed beneath the after part of the vessel. In the modified form shown in Figure 11, the strut E is curved backwards so as to present its convex leading edge towards the forward part of the vessel so that, as in Figure 10, the hydrofoils are arranged in echelon. The backward inclination or curvature of the struts, as described with reference to Figures 10 and 11, combined with backward sweeping of the hydrofoils as described with reference to any one of Figures 59, will tend to allow seaweed or the like with which the submerged struts and hydrofoils are liable to come into contact to be carried or to slide off downspect to the trailing edges of the hydrofoils.

It will be appreciated that though the angle of incidence of the hydrofoils as shown in Figures 11 and 12 is substantially the same for each foil, the angle of incidence of the upper foil or foils reference to Figure 10.

All the hydrofoils in a set may have the same inclination with respect to their horizontal plane, as illustrated for example in Figure 3.

the extremities H horizontal. In another arrangement, as illustrated in Figure 14, the portion J of each hydrofoil which lies nearest to the strut K has one inclination with respect to the horizontal, whilst the outer portion J of each foil has a greater inclination to the horizontal.

It will be understood that the constructions shown in the drawings are given by way of example only and, moreover, are illustrated purely diagrammatically.

Though in the constructions described with reference to Figures 1 and 2, and Figure 4, the laterally spaced struts B and B or B and B are in lateral alignment, it will be understood that the arrangement of the struts may be varied to suit requirements. Thus, more than two struts may be arranged to project downwardly from the forward portion of the vessel, and similarly a plurality of struts may be arranged to project downwardly from the after portion of the vessel, the forward or rearward struts being either in transverse alignment or otherwise. For example, if three transversely spaced struts are employed, say, under the forward portion of the vessel with the centre one arranged on the centre line of the vessel, the two lateral or associated struts may be placed somewhat to the rear of the central strut in relation to a common transverse line normal to the centre line of the vessel, a single or a plurality of struts extending downwards further aft. Again, where such a plurality of struts are provided, some only or all the struts may be rearwardly inclined or curved, this inclination or curvature differing or being the same for all the struts. The arrangement and disposition of the hydrofoils and the several struts may also differ.

It will be understood that in each case the vessel is provided with at least three struts, that is to say, if a single strut is provided on the centre line of the vessel adjacent to its forward portion, at least two struts are provided further aft, whilst, conversely, if a single strut is provided extending downwards from the after portion of the vessel, at least two struts are arranged to extend downwards from the forward portion of the vessel. It will, however, be appreciated that a vessel according to the invention may be furnished with more than three struts, say, one extending downwards from the forward portion of the vessel, two from the after portion thereof, and one or more from the intermediate part, say, on the central line of the vessel. If found desirable or necessary, stays may be carried between the forward and rear strutsor between each strut and the hull, such stays being arranged to lie in the vertical plane which contains the centre line of the vessel or in planes parallel to such central vertical plane.

Where two or more struts are arranged and spaced apart in a transverse direction under the mid or fore part of the hull, the structures of the lateral struts and the hydrofoils thereon are arranged so as to balance the hull both as to weight and the lifting effect of the hydrofoils. When there is dihedral or other relative angularity of the hydrofoils on a strut, such angularity may also be determined in relation to lateral movements of the vessel, as for instance when turning or rolling about a longitudinal axis.

The detail structure of each strut and the hydrofoils mounted thereon, as also the manner in which these hydrofoils are connected to the strut and the manner in which the strut is attached to the hull, may vary to suit requirements. For example, known practice in aerofoil shape and structure may be adopted for the hydrofoils in so far as appears desirable or practicable, having regard. to the fact that the foils are immersed in water and will not be functioning in the air.

What I claim as my invention and desire to secure by Letters Patent is:-

1. In a surface craft, in combination, a hull, at least three struts projecting downwardly and directly from the hull, at least one of the struts having its leading edge curved in profile, with the convexity of the curve directed towards the forward end of the hull, and a set of hydrofoils on each strut, the hydrofoils on the said curved strut having their leading edges swept backwards, with the hydrofoils mounted in forward echelon on the strut so that the leading and trailing edges of any one hydrofoil lie respectively further forward than the leading and trailing edges of the next lower hydrofoil, the hydrofoils of each strut, upon which hydrofoils the hull is supported clear of the water when speed is attained, being supported from the hull solely by that strut.

2. In a surface craft, in combination, a hull, at least three struts projecting downwardly and directly from the hull, at least one of the struts having its leading edge curved in profile with the convexity of the curve directed towards the forward end of the hull, and a set of hydrofoils on each strut, the hydrofoils on the said curved strut having their leading edges swept backwards, with the hydrofoils mounted in forward echelon on the strut so that the leading and trailing edges of any one hydrofoil lie respectively further forward than the leading and trailing edges of the next lower hydrofoil, with the leading edge of the strut projecting in advance of the leading edges of the hydrofoils carried by that strut, the hydrofoils of each strut, upon which hydrofoils the hull is supported clear of the water when speed is attained, being supported from the hull solely by that strut.

3. In a surface craft, in combination, a hull, at least three struts projecting downwardly and directly from the hull, and a set of hydrofoils on each strut, the hydrofoils on at least one strut being mounted in forward echelon thereon so that the leading and trailing edges of any one hydrofoil lie respectively further forward than the leading and trailing edges of the next lower hydrofoil, the angle of incidence of the uppermost hydrofoil exceeding that of a lower foil, the hydrofoils of each strut, upon which hydrofoils the hull is supported clear of the surface when speed is attained, being supported from the hull solely by that strut.

4. In a surface craft, in combination, a hull, at least three struts projecting downwardly and directly from the hull, at least one of the struts having its leading edge curved in profile with the convexity of the curve directed towards the forward end of the hull, and a set of hydrofoils on each strut, the hydrofoils on the said curved strut being mounted in forward echelon thereon r so that the leading and trailing edges of any one hydrofoil lie respectively further forward than the leading and trailing edges of the next lower hydrofoil, the angle of incidence of the uppermost hydrofoil exceeding that of a lower foil, the hydrofoils of each strut, upon which hydrofoils the hull is supported clear of the water when speed is attained, being supported from the hull solely by that strut.

5. In a surface craft, in combination, a hull, at least three struts projecting downwardly and directly from the hull, and a set of hydrofoils on each strut, the hydrofoils on at least one strut having their leading edges swept backwards, with the hydrofoils mounted in forward echelon on the strut so that the leading and trailing edges of any one hydrofoil lie respectively further forward than the leading and trailing edges of the next lower hydrofoil, the angle of incidence of the uppermost foil exceeding that of a lower foil, the hydrofoils of each strut, upon which hydrofoils the hull is supported clear of the surface when speed is attained, being supported from the hull solely by that strut.

10 on the strut so that edges of any one hydrofoil lie respectively further forward than the leading and trailing edges of the next lower hydrofoil, the trailing edge of the hydrofoils projecting behind the trailing edge of the strut, the hydrofoils of each strut, upon which hydrofoils the hull is supported clear of the water when speed is attained, being supported from the hull solely by that strut.

GEOFFREY CROMWELL EDWARD HAMPDEN. 

